Grinding machine



Aug. 23, 1932. w. F. FRASER GRINDING MACHINE Filed Oct. 2, 1930 3 Sheets-Sheet 2 INVENToR ATTORNEY Aug.23, 1932. w. F FRASER 1,873,752

' GRINDING MACHINE Filed Oct. 2, 1950 3 Sheets-Sheet 5 F1 gr Patented Aug. 23, 1932 1,873,752

UNITE' STATES FATE ,FFICE Appiication tied october 2, i930.` seiai iva-185,963.

This inventioiirelates to grinding ma- Fig. is a diagrammatic view showing a chines and is more especially concerned with valve-mechanism which maybe used to conthe means for supporting and positioning trol the operation of the work head shown the articles. of work for the grinding operain Fig-1;` y

5 tion. Fig; 6 is a side View o-f the valve-Aarrange- The invention will be herein disclosedas iii-ent shown in Fig. '5 illustrating the cam ap lied to the machine shown in my prior mechanism which controls its operation; and Patent No. 1,736,967, granted-November 26, Fig. 7 is a vertical sectional view illus- 1929. This machine is'de-signedparticulartrating another embodiment of the inven- 14" ly to lgrind bushings, pins,'rolls, and other tion'. l i f articles having cylindrical or tapered exter- .b The drawings show certain parts only of nal surfaces, and itis so organized as to vperthe machine illustrated in my prior patent form all of the grinding operations and those above designated, and reference should be ofmounting and releasing the work aliitomade tothe specificationv and drawings of 15 matically. Y f l said patent for a complete understanding O-f 15 It is the chief object of the invention furthe machine. Y

ther to improve and perfect the work sup- Referring first to Figs. 1', 2 and 3 the work porting and positioning mechanisms of mahead there shown is designed to be mounted chines of this general type with a viewv to in the machine shown in my patent aforesaid I .g

enabling them to handle a vwider variety of inplace of the work head 69 illustrated in work while still performing their various Fig. 10 of said patent. The new work head functions automatically. The invention is comprises a body or frame 2 which may be directed particularly to the provision of secured to the base of the machine by bolts mechanism for handling shoulderedr work 3*-3. VIt also includes a head stock whichr A such, for example, as shouldered bushings, comprises a spindle 4 journaled in suitable E and for supporting and positioning such arbearings supported in the frame 2 so that it ticles of work automatically forl the grinclcan have both a rotary motion and also an lng of either the cylindrical O1- Shoflldered axial movement. This spindle carries a surfaces, or both, to a high degree of ac-f WOIk CQIltQr-Hlg member 5 designed to coop- Cul-3G37. y f i Y erate with a similar centering member 6 of The nature of the invention will be readily the? 153.11 St0Ckt0`UDP0 the-.Work W for h understood from the following description grmdmg OPQMOHJVTQ@ @all SOCk 0911136? 6 when vread in connection with the accompa- Correspond? t0 the Part 4, Flg- 2: of my Pat' iiying drawings, and the novel features will ent aforesald and lt may be Supported m the 1 1 8L] be particularly, pointed out in the appended. mannel 'disc-1,05% m 1S ald patent OE by an al Clms Y rangement line that siiown in Fig. i or by any In the drawings l other convenient mechanism:y Y Y FU l ie of* Work heid um In order to rotate the spindle 4 it is conlrure ls a p a LV a nected with a shaft 7 of the machine by a 40 bodydng featurespf dus ltwenttonand Show" collar 8 which is slidably keyed to theire- Q@ mg 1t m Operative mtatlmshlp to the m11 duced end of the spindle in the same manner Stoel? Cenfer andthe gru-mg Wheel i that the shaft 103 of said patent is connected Flg- 1S m end elevatlon 0f the Work head to the spindle 71- ofthe machine there shown. Shown 1TF1g 1i V d n The head stock also includes a sleeve 10 I 45 F13 31S a Ve'tlcal SeCtlOlal VleW 0H 151161111@ which is keyed to the forward ror right-hand di) 3j3 .Fgl 0f the Work head ShOWIl in end, Fig. 3,'of the spindle 4 by 'a slidable con- F1gl; 0 Y iiection so that the sleeve and spindle are com- Fig. 4 is a horizontal sectional view of a pelled to rotate in unison, but the spindlecan niodied form of work holding and positionslide relatively to the sleeve. 'A housing 12 ing devices; Y v which is secured to thebody or frame 2 encloses the sleeve 10 and prevents any substantial movement of the sleeve toward the right, Fig. 3. This housing is also provided with a groove cooperating with vent holes in the sleeve 10 and with a hole 13 at the bottom of the housing to permit the escape of coolant used in the grinding operation. A ball thrust bearing 14 backs up the sleeve and prevents it from moving toward the left since it is itself backed up by the frame piece 2. The sleeve also is provided with a removable bushing 15 threaded into the end thereof and having an end face 16 which is adapted to engage with the end face of the work W and thereby determine the endwise position of the work, this bushing being supported in a fixed position by the parts just mentioned. Y

y For the purpose of relatively moving the work supporting and centering members 5 Vand 6 to engage or release the work, a collar 18 is secured rotatably on the spindle 4 and is held against axial movement in one direction by a shoulder 19 formed on the spindle and a ball thrust bearing 20 interposed between the collar 18 and t ie shoulder. Any substantial axial movement in the opposite direction is prevented by a collar 21 which is backed up by another collar`22 screw threaded on the spindle 4 and secured in an adjusted position by a set screw 23. lThe forked lower end of a bell crank lever 24 straddles the collar 18 and enters slots provided to receive it in the opposite sides of the collar. This lever also has a horizontal ar'm 25 which is operatively connected with the lower end of a piston rod 26 having a piston 27 secured to its Vupper end. The piston works in a short vertical cylinder 28 which is secured to the frame piece 2 by a bracket 30, the bracket also serving as a bearing and housing for the bell crank lever 24-25. Stop screws 231-81 threaded through the opposite walls of the bracket are positioned to engage the opposite sides of the lever arm 24 and t-o limit the range movement of this lever.

By controlling the supply and discharge of fluid under pressure to and from the cylinder 28 the spindle 4 can be made to advance intO contact with the work or to recede therefrom at any desired points in the cycle of operations of the machine. If the tail stock center 6 is positively moved by a cam mechanism as shown in Patent No. 1,786,967 the pressure exerted by it on the work will be sufficient to vovercome the opposing pressure applied through the` head stock center 5, and the end of the work will be held in Contact with the face 16 of the work positioning bushing 15. The position of the work longitudinally of the axis on which it revolves, therefore, will be accurately determined and when the grinding wheel 82 is advanced to face o the shoulder S on the work, or to grind the cylindrical surface of the work, or to perform bot-h functions, it will grind the shoulder to a definite Lec/335e and accurate relationship to the end of the Work which is abutted against the bushing 15.

Under some circumstances it is preferable to replace not only the head stock mechanism 69 of the machine shown in Patent llo. 1,736,- 967 with the work head above described, but also to replace the tail stock mechanism with a similarV arrangement. This is conveniently accomplished as shown in Fig. 7 by mounting the tail stock center 6 in a mechanism substantially like that shown in Figs. 1, 2 and 3. This mechanism comprises a spindle 4 in which the tail stock center 6 is supported, the spindle being mounted in the body 2 in essentially the same manner that the spindle 4 is supported in the body 2. Other parts arc associated with the spindle to rotate it and reciprocate it axially in substantially the same manner that the spindle 4 is operated` and these parts are indicated by corresponding but primed numerals.

The differential' pressure which the work supporting and centeringmembers 5 and 6 exert upon the work XV maybe produced either by using a. higher pressure in the cylinder 28 than in the cylinder 28, or by making the cylinder 28 and the piston 27 which Works in it of somewhat larger diameter than the corresponding parts 27 and 28 and using the same pressure in both cylinders. The latter method usually is preferable because it requires only one supply of fluid under pressure and accordingly this construction has been illustrated in Fig. 7. Due to this differential in pressure, the left-hand end of the work WV will always be held against the work positioning member 15 while the grinding operation is being performed.

As each piece of work, therefore, is delivered automatically to the centers 5 and 6, they will advance to engage the opposite ends of the piece, center it, and move it endwise until it abuts against the bushing 15, holding it in this position until the grinding operation has been performed and then withdrawing and allowing it to drop out of grinding position.

If the work consists of a bushing or other article which must be centered by its bore, n

it is preferable to replace the work centering and supporting members 5 and 6 with other centering members such as those indicated at 34 and 85, Fig. 4, the latter members having a slow taper to enter the opposite ends of the bore in the bushing B and form a supporting and driving connection therewith. In this construction also a differential pressure is applied through the spindles 4 and 4 to the work, the greater pressure being eX- erted through the spindle 4 and its centering device 35 to force the work against the positioning member 15. In this arrangement the bushing'15 acts not only as an end positioning device but also as a stripper to remove the work from the part 34 as the latter with- CII swam

draws after the completion of the grinding operation. A similar bushing is associated with the work supporting member 35.

Each -of these members projects through an aperture in its respective bushing and as the members withdraw to release the work the bushing B, which will tend to stick to one or the other of them, is stripped off by its contact with one of the partsl or 15.

A valve mechanism suitable for controlling the operation of the pistons 27 and 27 is shown in Figs. 5 and 6. It comprises a valve cylinder 36 having two bores to receive slidable valves 37 and 38, respectively. Fluid under pressure is delivered to the cylinders through pipes or tubes 40-40. Additional pipes or tubes 41-41 connect the valve cyl-` inder with the lower ends of the cylinders 28 and 28', while similar pipes 42-42 connect the upper ends of said cylinders with the valve cylinder; `The communicati-on'between these tubes and the supply pipes, or between the tubes and the exhaust ports 43 and '44 are controlled by the valves 87 and 38 in a manner which will be obvious to those skilled in this art. The exhaust ports both commiinicate constantly wth the exhaust or outlet pipe 45.

The operation of the two valves 37 and 38 is controlled by a cam 46, Fig. 6, on the cam shaft 47 of the machine, this shaft corresponding to the shaft 49 of the machine shown in my prior patent above designated. The cam acts through two rocker arms 48 and 49, respectively, which bear upon the upper ends of the respective valves 37 and 88. Springs 50 and 5l coiled about the shanks of the respective valves hold them upwardly against their rocker arms and force the rolls carried by the respective rocker arms againstV the surface of the cam 46. In the particular position shown in Fig. 5, fluid under pressure mayflow from the supply pipes 40-40 through the pipes 42-42 to the upper ends of the cylinders 28 and 28', thus forcing the pistons in these cylinders downwardly and holding the work centering devices 5 and 6 in their projected or work supporting positions. This is the normal condition during the grinding operation. When the cam 46allows the springs 50 and 51 to force the valves 37 and 38 upwardly, the fluid above the pistons in the cylinders 28 and 28 will be released and allowed to exhaust while fluid under pressure will be forced into the lower ends of the cylinders, thus lifting the pistons and causing both of the work centering devices 5 and 6 to recede and to release the work.

The invention thus enables a grinding machine of the general type shown in my earlier patent to handle and grind shouldered work automatically and with a high degree of acalso contemplated that the incuracy. Itis I be used in machines of other v-ention may types.

lof them having an' additional work positioningJmember'pprovided with a face against y which'to abut the'work to hol-d thework in a fixedpos'ition endwise of said axis, automatic mechanism for relatively moving said supporting members to yengage and release opposite endsof thev work and to force said work against said 'face-and hold it there against the pressure oppositely exerted thereon, and means for grinding the work so positioned.

2. In a. grinding machine, the combination of ahead stock, a tail stock cooperating with said head stock to sup'portxthe work for rotation about an axis, eachof said stocks having a rotary work supporting member and one of them having an additional work positioning member provided with a face against which to abut the work to hold the work in a fixed position endwise of saidv axis, fluid pressure operated mechanism for relatively moving said supporting members to engage and release opposite ends of the work, means for forcing the work endwise against saidface and holding it there against the pressure oppositely exerted onthe work, and means for grinding the work'so positioned.

3. A grindii'ig machine asdefin'ed in preceding claim 2 in which said iiuid pressure operating mechanism includes valve means forr controllingthe operation of said mechanisin; -a cam, and-means under the control. ofsaid cani for operating said valve mech,- anism. I

fili).-

' 4. In a grinding machine, the combination sure operated mechanism for moving bothV of said work supporting members into and outof operative engagement with opposite ends of the work, said mechanism being constructed and arranged to apply greater pres-v 1 sure to the work through one of said supporting members than through the other and thereby to hold the work abutted against said face, and-means for grinding the work so positioned.

' 5'. In a grinding machine, the combination of a head stock, a tail stock4 cooperating With said head stock to support the Work for` rotation about an axis, each of said-stocks having a rotary Work supporting member and one of them having an additional work positioning member provided with a vtace against Which to abut the Work to hold the Work in a Xed position endivise of said' axis, fluid pressure operated mechanism for moving both of said Work supporting members into and out of operative engagement With opposite ends of the Work, valve mechanism controlling the operation of said Huid pressure mechanism, a cam shaft, and means arranged to be operated by said cam shaft for actuating said valve mechanism.

6. In a grinding machine, the combination of a grinding Wheel, a head stock, a tail stock, each ot said stocks having a Work supporting member, a work positioning member independent of said Work supporting niembers but associated with one of said stocks and having a face against Which to abut the Work, said positioning` member having an aperture through which the Work supporting member associated With it may be projected into engagement with the Work, means including a thrust bearing for supporting said Work positioning member against the thrust of the Work and in a fixed position and automatic mechanism i'or relatively moving said Work supporting members into and out of engagement with the Work and for holding the Work against said face While the grinding operation is being performed. t

7. In a grinding machine, the combination of a head stock, a tail stock, said stocks having work centering members to engage opposite ends of the Work and support it for the grinding operation, automatic mechanism for relatively moving' said centering members to engage or release the Work, a Work position-` ing member independent of said Work centering members but associated with one of said stocks for abutting against an end face of the Work, means including a thrust bearing for supporting said Work positioning member against the thrust of the Work and in a ixed position, said mechanism being constructed and arranged to operate through one of said centering members to force the Work against said positioning member and to hold it thereagainst during the grinding operation, and means for grinding the Work so positioned.

VARREN F. FRASER. Y 

